David g



D. G. DEE.

FIRE- ALARM APPARATUS.

APPLICATION men JULY 25.1912.

1 1 Patented Aug. 15, 1916.

a n r entice,

DAVID DEE, OF ROCHESTER, NEW YORK, ASSIQNOR TO DENIO GENERAL ELECTRICCOMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

FIRE-ALARM APPARATUS,

Application filed July 25, 1912.

To ultwhom it 1f; (43/ concern Be it known that I, I)A\ll) G. DEE, ofRochester, in the county of Monroe and State of New-York, haveinvented'certain new and useful Improx'ements in Fire- "Alarm Apparatus;and I do hereby declare the following to be a full,'clear, and exactdescription of the same, reference being had to the accompanyingdrawings, forming a part of this specification, and to thereference-numerals marked'thereon. Y

My present invention relates to fire alarm 'apparatus,particularly tosystems to be used pointed out in the claims at the end of thespecification.

In the drawings: Figure 1 is a' diagrammatic view illustrating a callmechanism showing one embodiment of my present invention, and Fig. 2 isa detail view showing a modification thereof.

The apparatus embodying my present in vention is adapted to use inmunicipalities provided with telephone exchange systems, the fire alarmsignaling or calling instruments used in conjunctiontherewith beingadapted when set into operation, to transmit to the exchange operator,in addition to the impulses of current indicating the code signal of theinstrument, other impulses which vibrate the diaphragm of the operatorstelephone receiver, to audibly indicate that an alarm has been turnedin. The distinguishing signal is such that it may be immedi atelyrecognized by the exchange operator and not misunderstood, as a possibleline disturbance, such as an intermittent ground applied to the circuit,or other line trouble. The provision of means whereby the central.

office operator may be quickly informed of the character of the signalpossesses the advantage that it is unnecessary to wait until thesign-allng apparatus has been 1n operation for a length of timesufficient to permit a full Specification of Letters Patent.

Patented Au -.15; 1916.

Serial No. 711,471.

Y signal or round of the box to be turned .in, which would otherwise benecessary to distinguish such signal from some other effect which mightbe produced on the telephone line from outside causes. The idea ofquickly informing the telephone operator at the central exchange of thecharacter of the call which is being received is important in that thecalling circuit may be more quickly connected to the fire departmentheadquarters and a direct connection established between the subscribersalarm or calling apparatus and the alarmsounding and recording devicesof the fire department.

The present invention isapplicable to any form or type of signal boxwhich may be employed for transmitting a series of current impulses,orsuch impulses arranged in groups, the transmission of which willinclicate an alarm for some particular purpose despatched over thetelephone subscribers instrument circuit.

In illustrating my present invention, I have shown a telephonesubscribers instrument circuit, comprising the line wires AB leadingfrom the tip and sleeve contacts of the switch-board jack J; saidsubscribers circuit comprising the transmitter T and the receiver R,suspended on the usual receiver hook 1 1 The alarm mechanism indicatedby M may be located at any convenient point and will preferably comprisea clock train signal mechanlsm having the frame m and A from the contactspring 29.

The central oiiice apparatus, or switchboard mechanism', may be of theusual or any preferred construction and in the illust'rations I haveshown diagrammatically the answering and calling cord circuits indicatedby-lv and 2 respectively, receiving current from the battery 3, incircuit with which is the operators set comprising the receiver 4 andthe transmitter Associated with the to thefire' department headquarters,com-.

prising a plug S from the tip and sleeve contacts of which extend theline wires s-s. This private circuit is fedwith current from a batteryor other source of current 8 for actuating an electro-magnet acontrolling an armature s which is adapted to be moved into engagementwith the contact 8 said armature and contact being in a local circuit atthe fire alarm headquarters comprising the wires .9 ends connecting thebattery s and the electro-magnets s", by means of which the punch ormarker 8 is operated to record the fire alarm signal on a tape 8.

The object of my invention is to provide" in conjunction with thecircuit and alarm indicating mechanism described, means arranged in thealarm circuit whereby a distinctive signal is simultaneously transmittedover the line circuit with the transmission of the impulses of the alarmcode. In the ordinary operation of the alarm mechanism the pilot lamp jwill flicker or flash, in response to the impulses of currenttransmitted over the line circuit by the signaling mechanism. Theseflashes occurring at regular predetermined intervals and indicating thenumber of the fire alarm box in operation, cannot be distinguished bythe central operator, as the pilot light may be similarly operated fromother disturbances .on the telephone line, as for instance, by

the opening and closing of the receiver hook contact of a telephone set;an intermittent ground applied to the line; or an occasional shortcircuit thereon. For these reasons it isimpossible for the centraloiiice operator to determine' immediately between such causes of'troubleand the regular operation of the fire alarm box. This necessarily causesdelay in transmitting the signal to the fire headquarters, because ifthe operator is to make sure that the signal received is a proper firealarm signal, it is necessary to wait until, at least, one completeround of the signal box has been transmitted. This also retards thetraiiic on the switchboard, as the operator during this time, isprevented from responding to other calls.

The distinctive signal which I propose to use. is an audible onereceived by the central oflice operator in the receiver 4, produced bysuperimposing an induced current of frequent alternations on thecircuit, when it is closed through the signal box. One means of carryingout the invention consists in extending from theside B of the circuit .abranch B whichleads to the normally open contact spring 9. Thesubscribers instrument set is cut out when the numeral wheel a isrotating at the contacts 0 and 0. Provided in the branch B of thecircuit is an electro-magnet, having the windings Y) and the pole piecesin proximity to the'f'rec endsof which is arranged an armature G.Relative movement between the armature and the pole pieces is effectedby mounting one of these parts, as for instance, the armature, in such amanner that it maybe vibrated or agitated mechanically duringtheoperation of the alarm mechanism to vary the air gap between saidarmature and the pole pieces of the magnet, which causes a change in themagnetic flux' flowing therethrough and generates or induces in thewinding of the magnet an alternating" current thus superlmposing on theline a current whlch produces a distinctive signal- It is preferable.

that the vibration of the armature C should be 'apid, and to this end itmay be conveniently supported, as shown in Fig. 1, and agitated by ahammer or clapper m operated by the detent m which controls the speed ofoperation of the clock train.

In Fig. 2 I have shown a modified arrangement of the parts in which thewire 13, corresponding to the wire B, is provided with the winding Z2 ofan electromagnet, having the core pieces I), which are rigidly supportedon the casing M of the signal apparatus. In this form of the device thearmature (3 is shown supported upon the extremity of a spiral spring C,the inner end of which is attached to a rigid post C extending outwardlyfrom the rear wall of the case M, in such position that the spring maybe struck by the vibrating hammer m This form of'apparatus may beemployed where it is desiredto sound a warning signal in the alarm boxfor the benefit of persons who maybe in that vicinity as well as toprovide the distinctive signal for the central office operator. i

In operation, the alarm mechanism,'having-been actuated or set intoaction in the usual well known manner, becomes bridged across thesubscribers line circuit and each time said circuit is closed throughthe projections on the wheel 11. and wiper g the pilot light J attractsthe central office operators attention. The latter then places theanswering plug 1 in the jack J and during the periods the circuit isclosed the operator distinguishes the peculiarity of the audiblesignal,whereupon the answering plug 1 is removed and the special plug Sof the fire alarm circuit is inserted in the jack J. The intermittentimpulses of current then flowing over the circuit s-s energizes themagline circuits leading therefrom and supplied .net 8 causing acorresponding operation of the armature s and the recording device wires8, s 7 I claim as my invention:

1. The combination with a telephone system provided with an operatorsreceiver and subscribers line circu ts leading from the exchange, andsubscribers line signal, and a central battery current, of a fire alarmapparatus comprising a normally-open alarm circuit in COI1]L1IlCt1OI1with the subscribers line circuit, an alarm mechanism adapted to closeand open sai'dalarm circuit, means operatedthereby to operate the linesignal, and means operated by the alarm mechanism for superimposing analternating current on I said circuit when closed in addition to thebattery current to produce an audible signal in the central operatorsrece ver.

2. The combination with a telephone system comprising an exchange andsubscribers with battery when closed, each subscribers line circuitbeing provided with a line sig- .nal, of a fire alarm apparatuscomprising a normally open alarm circuit in conjunction with thesubscribers line circuit, an electromagnet in said alarm circuit, analarm mechanlsm adapted to cause current m-said circult to flow byimpulses for operating the line signal aforesaid, and means for varyingthe magnet flux in the core of said magnet,

during the transmission of such impulses, said flux variations producingan induced current in the winding of the magnet which is impressed uponthe line circuit when the alarm circuit is closed- 3. The combinationwith a centralenergy telephone system comprising subscribers linecircuits which are normally open and are supplied with battery currentfrom a central source when closed, each subscribers line circuit beingprovided with a central ofiice line signal, of a fire alarm mechanismadapted to cause said current to flow by impulses over a subscribersline circuit and thereby operate. the line slgnal thereof, and meansactuated by said mechanism for imposing an alternat- 111g current onsaid circuit during the transmission of the impulses,

i. A fire alarm system for telephone lines comprising a normally opencircuit leading from the said line and adapted when closed to close theline circuit and to beiener-gized by the current supplied to said linefrom the usual source, of. an electro-magnet arranged with its coil insaid circuit and means 00- operating with the pole pieces of said mag-'net for varying the magnetic flux flowing through the core of the magnetand means for closing and opening the alarm circuit.

5. A fire alarm system for telephone lines comprising a normally opencircuit leading from the said line and adapted When closed I to closethe line circuit and to be energized polepieceslocated adjacent andarranged with its coils in said circuit, of an armature cooperating withsaid pole pieces, 'means for effecting a relative movement between thepole pieces and armature to vary the air gap between them and means forclosing and opening said alarm circuit.

6. Thecombination with a subscribers telephone circuit-and a centraloilice equipment comprising an operators receiver and an alarm mechanismassociated with the circu'it for transmitting current impulses thcreonby opening and closing said circuit, of a magnet. winding interposed inthe circuit, and an armature therefore, arranged to be yibrated by theoperation of the alarm mechanism to induce an alternating current in themagnet which is superposed on the circuit to produce a distinctiveaudible signal in the operators receiver.

7. The combination with a telephone system comprisingan exchange havingan op-- erators receiver and subscribers line circuits and provided withcurrent from a cen tral source, of a fire alarm apparatus comprising anormally open alarm circuit, an alarm mechanism adapted to open andclose saidalarm circuit and subscribers line circuit for transmitting analarm signal over said alarm and subscribers line circuits, meanscontrolled thereby to operate a line signal, and means operating uponthe subscribers line andalarm circuits forgenerating and superimposingan alternating current upon said circuits when said alarmcircuit isclosed', in addition to the alarm signal impulses, to produce an audibleand distinctive signal in'the operators receiver.

8. The combination with a telephone system comprising an operatorsreceiver and subscribers line circuitsand provided with battery currentfrom a central source, of an alarm apparatus.associated with thesubscribers line circuit comprising a normally open alarm circuit and analarm mechanism adapted to open andclose both the alarm circuit and thesubscribers line circuit, thereby transmitting alarm signal im pulsesover said circuits from the central source of battery current, meanscontrolled thereby to operate the line signal, and means operable by thealarm mechanism for superimposing an alternating current on said alarmcircuit and said subscribers line cirimpulses aforesaid to produce anaudible distinctive signal in the operators receiver.

9. The combination with the telephone system comprising an exchangeprovided with an operators receiver and subscribers line circuits and aline signal, of an alarm apparatus comprising a normally open ciriaecuit associated with the subscribers line circuit, an alarm mechanismadapted to open and close said alarm circuit and said subscribers linecircuit, thereby sending alarm signal impulses over said circuit which0p erate the line signal, and means associated with the alarm circuitfor superimposing an alternating current on said alarm circuit and saidsubscribers line circuit upon the closing G. WILLARD RICH, RUSSELL B.GRIFFITH.

